Online Shop - Checkout

<?php
require_once 'library/config.php';
require_once 'library/cart-functions.php';
require_once 'library/checkout-functions.php';

if (isCartEmpty()) {
// the shopping cart is still empty
// so checkout is not allowed
header('Location: cart.php');
} else if (isset($_GET['step'])
&& (int)$_GET['step'] > 0
&& (int)$_GET['step'] <= 3) {
$step = (int)$_GET['step'];

$includeFile = '';
if ($step == 1) {
$includeFile = 'shippingAndPaymentInfo.php';
$pageTitle = 'Checkout - Step 1 of 2';
} else if ($step == 2) {
$includeFile = 'checkoutConfirmation.php';
$pageTitle = 'Checkout - Step 2 of 2';
} else if ($step == 3) {
$orderId = saveOrder();
$orderAmount = getOrderAmount($orderId);

$_SESSION['orderId'] = $orderId;

// our next action depends on the payment method
// if the payment method is COD then show the
// success page but when paypal is selected
// send the order details to paypal
if ($_POST['hidPaymentMethod'] == 'cod') {
header('Location: success.php');
exit;
} else {
$includeFile = 'paypal/payment.php';
}
}
} else {
// missing or invalid step number, just redirect
header('Location: index.php');
}

require_once 'include/header.php';
?>
<script language="JavaScript" type="text/javascript" src="library/checkout.js"></script>
<?php
require_once "include/$includeFile";
require_once 'include/footer.php';
?>

On top of this file we check if the shoppping cart is empty. If it is empty the customer is redirected to the cart page. Just to let her know that her shopping cart is still empty and so she cannot checkout.

Just like the main page ( index.php ) the checkout page "out sourced" almost everything to other pages. The main part of this file is the switch to load appropriate file depending on which checkout step the customer is on.

And now, let's take a better look at these checkout processes one step at a time.